This proposal requests funds to support the purchase of a major upgrade to the Siemens Trio 3 Tesla MRI system at the Georgetown University Center for Functional and Molecular Imaging. This new equipment will significantly enhance our current research projects by enabling more rapid structural imaging and more sensitive functional imaging in a much quieter operational environment. The existing system, which was initially funded by the Georgetown University Medical Center, has operated for two years as a core facility in support of a number of NIH funded research projects investigating alterations in brain function associated with a wide range of medical conditions, including developmental disorders, metabolic disorders, dementia, and cerebrovascular disease. The proposed equipment purchase incorporates a wide range of improvements to various parts of the imaging system and will provide a significant increase in this system's capabilities including: (1) an over 30dB decrease in scanner noise, (2) an over 100% increase in the system signal-to-noise ratio resulting from improvements in the radiofrequency coil design, (3) a significant increase in gradient performance, allowing more rapid acquisition of diffusion tensor image data and (4) a significant decrease in the time required for structural imaging, resulting from the expansion of the parallel image acquisition subsystem. Together these improvements will result in a substantial advance in overall system functionality, enabling more rapid structural, functional and metabolic studies. In particular, the reduction in imaging time and scanner noise is of great importance due to the large number of pediatric studies supported by the system. [unreadable] [unreadable]